Activation problem

Originally I have a parallel desktop liscence in my old MacBookAir but that's already expired. I'm using new MacBookPro now and just purchase a new liecence. I login to my account in Parallel website and purchased a liscence. When I try to activate it said "You have entered an upgrade key. Please confirm it with a key from the previous version." I can't find my previous key, what can I do?

 

Hello, please be informed that in order to activate Parallels Desktop for Mac Upgrade license you must have a Parallels Desktop legacy permanent license to act like the previous version key while activation. If you don't have any Parallels Desktop legacy permanent license, please provide us with the payment reference number or the Parallels Desktop license key, so that we can initiate the refund for your Parallels Desktop for Mac Upgrade license, so that you can purchase Parallels Desktop full license. Thanks.

 

Thank you very much for your reply. How to send you the Parallels Desktop license key?

 

I have same issue, I really don't get what's different between upgrade and full licence. can anyone help please?